Flexible skirt for air cushion vehicles



4 Sheets-Shet 1 J. H. BERTIN ETAL FLEXIBLE SKIRT FOR AIR CUSHION VEHICLES Inuemfars ean Henri Ber-Afr) LZZI e /CL W Hoyney:

Sept. 5, 1967 Filed July 6, 1965 Sept. 5, 1967 BERT|N ET AL 3,339,654

FLEXIBLE SKIRT FOR AIR CUSHION VEHICLES Filed July 6, 1965 4 Sheets-Sheet .2

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FLEXIBLE SKIRT FOR AIR CUSHION VEHICLES Filed July 6, 1965 45heets-Sheet s Fig. 4

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FLEXIBLE SKIRT FOR AIR CUSHION VEHICLES Filed July 6, 1965 4 Sheets-Sheet 4 United States Patent FLEXIBLE SKIRT FOR AIR CUSHION VEHICLES Jean Henri Bertin, Neuilly-sur-Seine, and Paul Francois Guienne, Paris, France, assignors to Bertin & Cie, Paris,

France, a company of France Filed July 6, 1965, Ser. No. 469,818 Claims priority, application France, July 7, 1964, Patent 980,972 12 Claims. (Cl. 180-7) French patent of addition No. 80,047 describes groundelfect vehicles or platforms resting at least partly on a plurality of unit air cushions bounded by flexible skirts which are surrounded by a peripheral flexible skirt with the unit skirts and the lobes of the peripheral skirt having a circular planform.

It is the object of the present invention to provide improved skirtings which, while retaining the characteristic of stability constituting the basic advantage of circular skirts, have a planform which follows an angular outline whereby a lift surface is provided, both at ground level and level with the undersurface of the platform, which is greater than that obtainable with circular lobes.

The invention has more particularly for its object to provide a flexible leg or cornerpost which is adapted to yield momentarily in the event of an obstacle being encountered by the skirt with which it cooperates but which opposes the tension in that skirt whereby to impart to the same a prescribed non-circular outline in planform, more specifically a platform in the shape of a curvilinear-sided polygon.

In a preferred form of embodiment such legs are positioned at the four corners of a rectangular platform in such manner as to impart to the lobes of a peripheral skirt dependent from said platform a lower contour that departs from a circular arm to assume a near-rectangular shape. Each inflatable leg consists of a frusto-conical envelope made of flexible material which is leaktight in respect of the inflating fluid, and this envelope has its base fixed to the underneath surface of the platform.

The description which follows with reference to the accompanying non-limiting exemplary drawings will give a clear understanding of the various particularities of the invention and of the art of carryingthem into effect.

In the drawings,

FIGURE 1 is an underneath view on a reduced scale of an improved platform comprising fou-r flexible legs according to the invention.

FIGURE 2 is a corresponding schematic side elevation view.

FIGURE 3 is a diametrical sectional view on an enlarged scale of a permanently inflated flexible leg and of the adjacent parts of the platform.

FIGURE 4 is a corresponding underneath view of a platform corner, with the leg being shown to be inflated by an ordinary valve by way of an alternative form of embodiment.

FIGURE 5 is a view similar to FIGURE 4, showing an alternative embodiment.

FIGURE '6 is a section taken along line VIVI of FIGURE 5.

Referring to the accompanying drawings, there is shown thereon a platform 1 supported by multiple air cushions 6 preferably supplied independently through ducts 2 and bounded by unit circular skirts 4 which are in turn surrounded by a peripheral skirt 3.

The peripheral skirt 3 has its upper edge fixed to the undersurface of the platform along a rectangular perimeter' with rounded corners. This skirt comprises two lobes separated by a partition wall 11 which prevents the lower edges of the sides of the skirt from moving away from each other, at least locally. Flexible legs 5 of curved cross-section cooperate with the wall 11 whereby to impart to the lower edge 10 of each of the two lobes of peripheral skirt 3 a planform that departs from the circular arcuate form to which the edge 10 tends in its relaxed state and assumes a near-rectangular shape with rounded instead of sharp corners.

FIGURES 3 and 4 show in detail the manner in which each leg and the adjacent parts of the peripheral skirt and the undersurface of the planform are devised.

The leg itself is formed of a frusto-conical envelope 501 made of gastight flexible material, an example being a neoprene-base material. The smaller base of this envelope (the one nearer to the ground) is gastightly sealed by a rigid plug 16, an example being a plug moulded out of a likewise neoprene-base material bonded at its periphery against said envelope 5a. The larger base is closed by a dished diaphragm 13 which is also bonded at its periphery 13a to the free edge 14 of envelope 5a, with possible inclusion of a circular stiffening member 12.

Dependent from the undersurface of platform 1, in a position adjacent one of the corners thereof as seen in plan view, is a circular support 15a having on its periphery a series of raised splines 15b separated by grooves. A collar 19 clamps the free edge 14 of envelope 5a against the support 15a, 15b whereby t0 rigidly unite said support with the leg 5. The peripheral skirt 3 is secured at its upper edge between the dependent flange of an angle-iron 20 fixed to the lower periphery of the platform and a flat split lockring 21 for instance. Adjacent one of the legs 5, the peripheral skirt 3 may comprise a section 7 rigidly connected to that leg along at least one outer longitudinal line of the frusto-conical envelope 5a. The section 7 may be suitably shaped so as to join into the remainder of the skirt along two lines 8.

In accordance with a first form of embodiment shown in FIGURE 3, the envelope 5a, may be continuously distended by any appropriate source of pressurized gas carried by the platform, such as for example the supply system to the ejector nozzles used for distending the skirts. A pipe 22 connected to this system and embodying a cutoff valve 23 is extended by a flexible line 22a having port within the leg after passing through the diaphragm 13 which closes the upper base of the frusto-conical envelope 5a. An overpressure or relief valve 24 may be inserted into the line 22a to prevent accidental bursting of the leg.

Reference is lastly had to FIGURE 4 for an alternative constructional form in which the leg is inflated solely on the occasion of a platform overhaul, using a valve 17 extending through both the peripheral ski-rt section 7 in contact with envelope 5a, and the envelope 5a itself.

In the example illustrated the skirt 3 is supplied simply by the supporting fluid escaping from beneath the lower edge 9 of the skirts 4. The lower edge 10 of skirt 3 is preferably slightly lower than the smaller bases 16 of the legs 5.

In operation, the pull on the peripheral skirt 3 will bend the legs 5 inwardly of said skirt to a small extent.

The embodiment illustrated in FIGURES 5 and 6 only differs from the previous one in that the flexible leg 5 secured under the lower surface of the vehicle is outside the outline of the peripheral skirt 3 instead of being inside. In this case, the skirt is connected to the leg along a narrow width surface s which is limited by lines g1, g2. This connection may be carried out in any convenient way, for example by sticking or by mean of stitching points along lines g1, g2.

It goes without saying that many changes and substitution-s of parts may be made to the forms of embodiment hereinbefore described without departing from the spirit and scope of the invention. It particular, any convenient flexible material may be used for the resilient legs, most notably at the points of attachment thereof to the platform, and their cross-section may be of any desired shape. Further, the cut-off valves 23 for continuously distending the legs may be remote-controlled.

What is claimed is:

1. A ground effect machine or like body movable along a bearing surface and having a rigid frame and a fluidpressurizable skirt made of thin, sheet-like, flaccid, fluidtight material and extending from said rigid frame to- Ward said surface, wherein the improvement comprises resiliently yieldable, skirt stretcher corner-posts projecting from said rigid frame toward said surface and engaging longitudinally said skirt at spaced locations thereof to stretch transversely said skirt between said corner-posts and to determine relatively sharp corners along the planform outline of said skirt with substantially circular arcuate sides thereof extending laterally from said corners, whereby said skirt outline assumes the general shape of a curvilinear-sided polygon, the apices of which are positioned at said corner-posts.

2. Body as claimed in claim 1, wherein said cornerposts have a rounded outer surface engaging saidskirt to form rounded apices for said polygon.

3. Body as claimed in claim 2, wherein said comerposts have a revolution shape of circular cross-section.

4. Body as claimed in claim 3, wherein said cornerposts are of frusto-conical shape.

5. Body as claimed in claim 1, wherein said cornerposts comprise a hollow inflatable member.

6. Body as claimed in claim 5, further comprising means for supplying pressure fluid to said hollow member to inflate the same.

7. Body as claimed in claim 6, further comprising relief valve means fitted to said inflatable member for limiting the fluid pressure therein.

8. Body as claimed in claim 1, wherein said cornerposts are positioned inside said skirt and engage the inner skin thereof.

9. Body as claimed in claim 1, wherein said cornerposts are positioned outside said skirt and engage the outer skin thereof.

10. Body as claimed in claim 1, wherein said cornerposts end short of the edge of said skirt adjacent said bearing surface.

11. Body as claimed in claim 1, further comprising bracing means extending between opposite arcuate skirt stretched sides at points thereof intermediate adjacent corner-posts, whereby said points are positioned in mutual spaced relationship.

12. Body as claimed in claim 1, further comprising a plurality of laterally spaced, fluid pressurizable skirts positioned inside said polygonal skirt and ending with substantially circular orifices opposite said bearing surface.

References Cited UNITED STATES PATENTS 3,078,940 2/1963 Rolle 1 7 3,180,443 4/1965 Jones -7 3,219,135 11/1965 Bunting et al 180-7 3,248,086 4/ 1966 Cockerell 1'807 X 3,252,536 5/1966 Jones 180-7 FOREIGN PATENTS 80,047 1/ 1963 France.

A. HARRY LEVY, Primary Examiner. 

1. A GROUND EFFECT MACHINE OR LIKE BODY MOVABLE ALONG A BEARING SURFACE AND HAVING A RIGID FRAME AND A FLUIDPRESSURIZABLE SKIRT MADE OF THIN, SHEET-LIKE, FLACCID, FLUIDTIGHT MATERIAL AND EXTENDING FROM SAID RIGID FRAME TOWARD SAID SURFACE, WHEREIN THE IMPROVEMENT COMPRISES RESILIENTLY YIELDABLE, SKIRT STRETCHER CORNER-POSTS PROJECTING FROM SAID RIGID FRAME TOWARD SAID SURFACE AND ENGAGING LONGITUDINALLY SAID SKIRT AT SPACED LOCATIONS THEREOF TO STRETCH TRANSVERSELY SAID SKIRT BETWEEN SAID CORNER-POSTS AND TO DETERMINE RELATIVELY SHARP CORNERS ALONG THE PLANFORM OUTLINE OF SAID SKIRT WITH SUBSTANTIALLY CIRCULAR ARCUATE SIDES THEREOF EXTENDING LATERALLY FROM SAID CORNERS, WHEREBY SAID SKIRT OUTLINE ASSUMES THE GENERAL SHAPE OF A CURVILINEAR-SIDED POLYGON, THE APICES OF WHICH ARE POSITIONED AT SAID CORNER-POSTS. 